Greater Melbourne in 2018: warmer than average with mostly below average rainfall

Rainfall in Melbourne during 2018 was generally below average; most months were drier than average, with February, April and September
very much drier than average across Greater Melbourne. Both maximum and minimum temperatures were warmer than average
throughout Greater Melbourne.

The highest daily rainfall total in Greater Melbourne during the year was 67.8 mm at Powelltown on 12 May, when a complex
low pressure system brought widespread rainfall to the Melbourne metropolitan area

The wettest place in Greater Melbourne in 2018 was Gladysdale (in the Yarra Ranges) with annual rainfall of 1086.8 mm

Warmer than average

At all sites in Greater Melbourne, mean maximum temperatures for the year ranged between 0.5 °C and
1.5 °C above average

Mean minimum temperatures were also warmer than average at most reporting sites, except
at Viewbank, where it was equal to annual average

In January,
April, and
October
all reporting sites across Greater Melbourne had mean maximum temperatures very much above average for
the respective months

The highest annual daytime temperature in the Melbourne metropolitan area
was 43.1 °C on 6 January at Laverton RAAF

In June,
clear skies and light winds under high pressure systems resulted in cooler than average night-time temperatures,
with most sites in Greater Melbourne reporting temperatures between 0.5 °C and 1.5 °C below June average

Towards the end of August,
clear skies, light winds and cold, dry air resulted in a more than a week of colder than average nights; the coldest
night-time temperature in the Melbourne metropolitan area during the year, -4.2 °C, was recorded on 29 August

September
was another month with below average night-time temperatures; averaged across all reporting sites, it was the coldest
September in Greater Melbourne since 1994

In contrast, night-time temperatures in January and
December were warmer than average for the respective months. The highest night-time temperature in Greater Melbourne, 28.5 °C,
was recorded at Moorabbin Airport on 29 January

Melbourne (Olympic Park)

Melbourne (Olympic Park)
site experienced equipment outages on 9 and 10 October and the total daily rainfall on these two days is not known. Based on the
surrounding sites, it is estimated that 3 to 5 mm fell on these two days, in addition to the 514.4 mm measured during the year

The mean daily maximum temperature for Melbourne (Olympic Park) was 20.8 °C. The warmest day was 41.7 °C on 6 January, and the coolest day was on 28 June when the temperature reached 10.6 °C

The mean daily minimum temperature for Melbourne (Olympic Park) was 11.7 °C. The coldest morning was 0.8 °C on 29 August, and the warmest morning was on 29 January when the minimum temperature was 27.8 °C

Notes

The annual climate summary lists the main features of the weather in Greater Melbourne using the most timely and accurate information available on the date of publication; it will generally not be updated. More extensive discussion of significant weather events, along with later information and data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review.
The Australian annual climate statement provides a comprehensive summary of Australia's climate during 2018. Information about changes and long-term trends in Australia's climate can be found in State of the Climate 2018.

This summary includes data from observing sites in or near the Greater Melbourne “Greater Capital City Statistical Area” (GCCSA). The Australian Bureau of Statistics designed the GCCSAs to “include the population within the urban area of the city, as well as people who regularly socialise, shop or work within the city, and live in small towns and rural areas surrounding the city. It is important to note that GCCSAs do not define the built up edge of the city. They provide a stable definition for these cities and are designed for the output of a range of social and economic survey data.”

This statement has been prepared based on information available at
12 pm on Friday 4 January 2019.
Some checks have been made on the data, but it is possible that results will change
as new information becomes available.

In some situations, some or all of the rainfall is in the form of hail or snow.
In these cases the totals given are for the water equivalent:
the depth of liquid water that results from melting any frozen precipitation.
There can be significant 'undercatch' of snow in strong winds,
meaning the true precipitation can be higher than that reported.

Averages for individual sites are long-term means based on observations from
all available years of record, which vary widely from site to site.
They are not shown for sites with less than 10 years of record, as they cannot then be calculated reliably.
The median
is sometimes more representative than the
mean
of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site,
based on the
decile ranking
(very low rainfall is in decile 1, low in decile 2 or 3,
average in decile 4 to 7, high in decile 8 or 9
and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a
percentage of the long-term mean.

Where temperature area averages are mentioned, they are derived from the
ACORN-SAT dataset.